Al-Mg series welding wire, preparation method and application thereof

Abstract

The present invention provides an Al-Mg welding wire, a preparation method and application thereof. The method comprises: melting and casting alloy raw materials according to the composition ratio, obtaining aluminum alloy cast rods, and sequentially performing homogenization treatment, extrusion, hot rough rolling, hot finishing rolling, drawing and coiling to obtain Al-Mg welding wire; wherein, hot rough rolling and hot finishing rolling also use hot finishing rolling emulsion, the mass concentration of hot rough rolling emulsion is greater than the mass concentration of hot finishing rolling emulsion, and the pH of hot rough rolling emulsion is less than the pH of hot finishing rolling emulsion. The present invention controls the alloy composition and uses homogenization treatment and extrusion process to make the alloy elements evenly distributed, effectively eliminates component segregation, makes the welding wire have higher strength, and improves the wire processing performance; at the same time, adopts a reasonable wire processing technology, and regulates the rolling emulsion composition to improve the surface quality of the welding wire, and the prepared finished welding wire can ensure the stable combustion of the arc and the molten pool during welding, and effectively improves the weld quality.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to an Al-Mg series welding wire, a preparation method and application thereof. Background Art

[0002] Al-Mg welding wire is the most commonly used series of aluminum alloy welding wires, with high strength and high toughness. It is used in aerospace, marine ships, rail transit and other fields. However, there are still some differences between domestic welding wires and imported welding wires, which are manifested in poor surface quality and difficulty in ensuring batch stability. Welding wires are usually produced by "continuous casting and rolling". This preparation method has the characteristics of low cost and high efficiency, but due to its equipment characteristics, the surface quality is difficult to guarantee.

[0003] At present, there are still shortcomings in the domestic production of high-end aluminum alloy welding wires, making it difficult to achieve domestic substitution of imported welding wires. In particular, in the fields of aerospace, marine ships, and rail transportation, welding wires not only need to have excellent mechanical properties, but their surface quality must also meet strict standards to ensure stability during welding and the quality of the weld. However, the current Al-Mg welding wires are difficult to achieve both high strength and good surface properties, which is not conducive to further improving the quality of the weld. Summary of the invention

[0004] The main purpose of the present invention is to provide an Al-Mg series welding wire, a preparation method and application thereof, so as to solve the problem that the Al-Mg series welding wire in the prior art is difficult to achieve high strength, high surface quality and low weld defects.

[0005] In order to achieve the above-mentioned object, according to one aspect of the present invention, a method for preparing an Al-Mg welding wire is provided, wherein the Al-Mg welding wire comprises, by weight percentage: Si≤0.05%, Fe≤0.12%, Cu≤0.01%, Mn≤0.55%, 5.6%≤Mg≤6.6%, Ti≤0.08%, and the balance is Al and unavoidable impurity elements, single impurity ≤0.05%, and total impurity ≤0.15%; the preparation method comprises the following steps: step S1, smelting and casting the alloy raw materials according to the composition ratio to obtain an aluminum alloy cast rod; step S2, homogenizing the aluminum alloy cast rod processing to obtain an aluminum alloy billet; step S3, extruding the aluminum alloy billet to obtain an aluminum alloy extruded rod; step S4, performing hot rough rolling on the aluminum alloy extruded rod, and using a hot rough rolling emulsion for the hot rough rolling to obtain a hot rough rolled wire; step S5, performing hot finish rolling on the hot rough rolled wire, and using a hot finish rolling emulsion for the hot finish rolling to obtain a hot finish rolled wire; step S6, drawing the hot finish rolled wire to obtain a drawn wire; step S7, coiling the drawn wire to obtain an Al-Mg welding wire; wherein the mass concentration of the hot rough rolling emulsion is greater than the mass concentration of the hot finish rolling emulsion, and the pH of the hot rough rolling emulsion is less than the pH of the hot finish rolling emulsion.

[0006] Furthermore, the mass concentration of the hot rough rolling emulsion is 7-10%, and the pH value is 6-7; and / or the mass concentration of the hot finishing rolling emulsion is 6-6.9%, and the pH value is 7.1-8.

[0007] Furthermore, independently, by weight, the hot rough rolling emulsion and the hot finishing emulsion include 50-70 parts of mineral oil, 10-15 parts of trimethylol oleate, 5-10 parts of aliphatic hydrocarbons, 5-8 parts of dihydrated benzyldimethyltetradecylamine, 3-6 parts of ethoxylated fatty alkylamine, 3-5 parts of sodium petroleum sulfonate, 1-3 parts of N,N-dimethyldodecylamine N-oxide and 0.1-0.5 parts of phenolic antioxidant.

[0008] Furthermore, the starting rolling temperature of the hot rough rolling is 500-530°C; and / or the starting rolling temperature of the hot finish rolling is 400-440°C.

[0009] Furthermore, in step S6, drawing oil is also used for drawing, and the viscosity of the drawing oil is 90-110 mm 2 / s, density is 0.8~1.0g / cm 3 .

[0010] Furthermore, the wire drawing oil includes, by weight, 20 to 30 parts of mineral oil, 40 to 50 parts of polyisobutylene, 15 to 25 parts of fatty acid ester, 10 to 15 parts of pentaerythritol ester and 1 to 3 parts of aniline antioxidant.

[0011] Furthermore, the casting temperature is 720-760° C.; and / or the homogenization temperature is 450-500° C., and the holding time is 10-24 hours.

[0012] According to another aspect of the present invention, there is provided an Al-Mg series welding wire obtained by using the above-mentioned preparation method of the present invention.

[0013] Furthermore, the strength of the Al-Mg welding wire is 450~500MPa, and the strength of the deposited metal is 300~340MPa.

[0014] According to another aspect of the present invention, a welding joint is provided, which is obtained by welding the Al-Mg series welding wire of the present invention and a 5XXX series plate, and the weld grade is Grade I.

[0015] By applying the technical solution of the present invention, the alloy composition is controlled, and the alloy elements are evenly distributed through homogenization treatment and extrusion process, so that the component segregation is effectively eliminated, the welding wire has higher strength, and the wire processing performance is improved; at the same time, a reasonable wire processing technology is adopted, and the rolling emulsion composition is regulated to improve the surface quality of the welding wire, so that the surface is flat, smooth, and free of scratches. The prepared finished welding wire can ensure the stable combustion of the arc and the molten pool during the welding process, thereby reducing defects such as weld porosity and effectively improving the weld quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0017] Figure 1 The surface quality diagram of the Al-Mg welding wire according to Example 1 of the present invention is shown;

[0018] Figure 2 A photo of a welded joint according to Example 1 of the present invention is shown;

[0019] Figure 3 The engineering stress-strain curve of the welded joint according to Example 1 of the present invention is shown. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] Terminology explanation:

[0022] Deposited Metal: It is the weld metal formed completely by melting the filler metal, and is the melted part of the electrode or wire in the weld.

[0023] As described in the background of the present invention, there is a problem in the prior art that Al-Mg welding wire is difficult to achieve high strength, high surface quality, and low weld defects. In order to solve the above problems, in a typical embodiment of the present invention, a method for preparing Al-Mg welding wire is provided. In terms of weight percentage, Al-Mg welding wire includes: Si≤0.05%, Fe≤0.12%, Cu≤0.01%, Mn≤0.55%, 5.6%≤Mg≤6.6%, Ti≤0.08%, and the balance is Al and unavoidable impurity elements, single impurity ≤0.05%, total impurity ≤0.15%; the preparation method includes the following steps: step S1, smelting and casting the alloy raw materials according to the component ratio to obtain aluminum alloy cast rods; step S2, homogenizing the aluminum alloy cast rods The aluminum alloy billet is homogenized to obtain an aluminum alloy billet; step S3, the aluminum alloy billet is extruded to obtain an aluminum alloy extruded rod; step S4, the aluminum alloy extruded rod is subjected to hot rough rolling, and a hot rough rolling emulsion is also used for the hot rough rolling to obtain a hot rough rolled wire rod; step S5, the hot rough rolled wire rod is subjected to hot finish rolling, and a hot finish rolling emulsion is also used for the hot finish rolling to obtain a hot finish rolled wire rod; step S6, the hot finish rolled wire rod is drawn to obtain a drawn wire rod; step S7, the drawn wire rod is coiled to obtain an Al-Mg welding wire; wherein, the mass concentration of the hot rough rolling emulsion is greater than the mass concentration of the hot finish rolling emulsion, and the pH of the hot rough rolling emulsion is less than the pH of the hot finish rolling emulsion.

[0024] Specifically, the present invention first melts and casts the alloy raw materials according to the composition ratio to obtain an aluminum alloy cast rod. Among them, the contents of Si, Fe, Cu, and Mn are strictly controlled at a low level, mainly to reduce defects in the welding process. For example, excessive Si and Fe content will lead to the formation of brittle intermetallic compounds, affecting the toughness of the weld; low Cu content helps to reduce thermal cracks; a small amount of Mn can improve the toughness of the weld and help to refine the weld grains.

[0025] The above-mentioned Mg content, as the main strengthening element, can significantly improve the strength and hardness of the welding wire while maintaining good corrosion resistance. The content is between 5.6% and 6.6% in order to achieve the best balance between strength performance and welding performance. Too high or too low Mg content will affect the plasticity of the welding wire and the fluidity of the molten metal during welding, thereby affecting the quality of the weld. It is preferably between 6.2% and 6.5%.

[0026] The right amount of Ti can refine the grains of welding wire and weld and improve the toughness of welding wire and weld. Controlling the inevitable impurity elements such as Cr and Zn within a reasonable range helps to maintain the purity of welding wire, reduce the impact of impurities on welding wire performance, and improve the strength performance and surface quality of welding wire.

[0027] Among them, the alloy raw material can be a pure alloy ingot or an intermediate alloy. The casting process can use electromagnetic stirring to make the elements evenly distributed, adopt two-stage online degassing, and then introduce it into the crystallizer for casting to reduce oxides and inclusions, thereby improving the internal structure and surface quality of the welding wire.

[0028] After obtaining the aluminum alloy cast rod, it is subjected to homogenization treatment and extrusion treatment in sequence to make the alloy elements evenly distributed, effectively eliminate component segregation, make the welding wire have higher strength, and improve the plastic processing performance of the wire, avoid wire breakage and other situations, so as to achieve the purpose of refining grains, improving strength and improving surface quality, and obtain aluminum alloy extruded rods. Then the aluminum alloy extruded rods are subjected to hot rough rolling and hot finishing rolling in sequence. The rough rolling process uses an emulsion with differentiated concentration and pH to reduce friction and improve surface quality to obtain hot finishing rolled wire. Finally, the hot finishing rolled wire is drawn to further refine the grains, improve the surface smoothness of the welding wire, reduce surface defects, and improve the wire feeding stability of the welding wire. The drawn wire is coiled to obtain Al-Mg series welding wire. Among them, the hot rough rolling emulsion and the hot finishing emulsion are both water-based emulsions.

[0029] It should be noted that the present invention limits the mass concentration of the hot rough rolling emulsion to be greater than the mass concentration of the hot finishing emulsion, and the pH of the hot rough rolling emulsion is less than the pH of the hot finishing emulsion. The purpose is to improve the surface quality of the wire in combination with the wire drawing operation, reduce defects such as pits and scratches, and lay the foundation for subsequent processing into brightened welding wire.

[0030] Specifically, during the hot rough rolling process, the high concentration of the emulsion can provide better lubrication, reduce friction between the rollers and the wire, and prevent surface damage such as scratches. The emulsion with a lower pH value has a good oil-water separation effect, more oil is separated, and its lubrication effect is better.

[0031] During the hot finishing rolling process, the concentration of the emulsion is relatively low, which is mainly beneficial for the small diameter wire rod to bite into the roller to avoid slipping, and reduce the emulsion residue, because too much emulsion residue may cause surface defects in the subsequent drawing and heat treatment process. Low concentration emulsion is also easy to clean, which is beneficial to improve the cleanliness of the wire surface and obtain welding wire with high surface quality. In the hot finishing rolling stage, the use of an emulsion with a higher pH value can make the preparation process more stable, ensure a higher yield rate during the continuous rolling process, and also help to make the wire have a higher surface finish.

[0032] The differentiated hot rolling emulsion solution of the present invention can not only ensure the processing performance of the material, but also take into account the surface quality of the welding wire, which helps to make the Al-Mg series welding wire have both high strength and high surface quality.

[0033] In summary, the present invention controls the alloy composition and uses homogenization and extrusion processes to make the welding wire have higher strength; at the same time, a reasonable wire processing process is adopted, and the rolling emulsion composition is regulated to improve the surface quality of the welding wire, so that the surface is smooth and has no quality problems such as scratches. The prepared finished welding wire can ensure the stable combustion of the arc and the molten pool during the welding process, thereby reducing defects such as weld porosity. The welding wire obtained by the method of the present invention has good continuous wire feeding stability, and the strength of the deposited metal and the quality of the welded joint are greatly improved.

[0034] In a preferred embodiment, the mass concentration of the hot rough rolling emulsion is 7-10%, and the pH value is 6-7; and / or the mass concentration of the hot finishing rolling emulsion is 6-6.9%, and the pH value is 7.1-8. Among them, the pH value can be controlled by adding an acid or alkali (such as an organic acid or an organic amine, the organic acid can be one or more of acetic acid, oxalic acid, malic acid, citric acid or other types of organic acids, and the organic amine can be one or more of ethylenediamine, triethanolamine, aniline or other types of organic amines). The use of the above-mentioned high-concentration, low-pH emulsion in the hot rough rolling stage can provide better lubrication and surface cleaning effects, which helps to maintain the high strength and plasticity of the wire. The use of the above-mentioned low-concentration, high-pH emulsion in the hot finishing rolling stage can further improve the surface quality of the wire, which is conducive to making the surface of the finished welding wire smooth and defect-free.

[0035] Based on similar reasons, in a preferred embodiment, independently, by weight, the hot rough rolling emulsion and the hot finishing emulsion include 50-70 parts of mineral oil, 10-15 parts of trimethylol oleate, 5-10 parts of aliphatic hydrocarbons, 5-8 parts of dihydrated benzyldimethyltetradecylamine, 3-6 parts of ethoxylated fatty alkylamine, 3-5 parts of sodium petroleum sulfonate, 1-3 parts of N,N-dimethyldodecylamine N-oxide and 0.1-0.5 parts of phenolic antioxidant. Among them, in the mineral oil solvent environment, fatty hydrocarbons can provide good lubrication and cooling properties, while also protecting the metal surface and reducing oxidation and corrosion; benzyl dimethyltetradecylamine dihydrate and N,N-dimethyldodecylamine N-oxide as surfactants can reduce the surface tension of the oil-water interface, form a stable dispersed emulsion, provide good lubrication effect, reduce friction during rolling, and help maintain the high strength and surface integrity of the welding wire material; ethoxylated fatty alkylamines help maintain the stability of the emulsion, reduce the generation of foam, and ensure the cooling and lubrication effects of the emulsion; phenolic antioxidants can prevent the base oil and additives in the emulsion from oxidation at high temperatures, and maintain the stable performance of the emulsion.

[0036] Through the reasonable proportion and use of the above ingredients, the hot rough rolling emulsion and hot finishing emulsion can not only provide good cooling, lubrication and anti-corrosion effects, reduce surface defects such as scratches and oxidation during processing, but also ensure the strength and plasticity of the welding wire material at high temperatures, thereby achieving the preparation goals of high strength and high surface quality of Al-Mg welding wire. In the hot rough rolling stage, by controlling the above emulsion to a high concentration and a low pH value, efficient processing of large diameter wires can be achieved while protecting the surface quality; and in the hot finishing stage, by controlling the above emulsion to a low concentration and a high pH value, the surface treatment of the wire can be more carefully controlled to ensure that the surface finish and strength of the final finished welding wire are in the optimal state.

[0037] In order to be more conducive to the coordination of a specific emulsion, so that the Al-Mg series welding wire can exhibit the characteristics of high strength and high surface quality after processing, meet the requirements for the use of the welding wire, and obtain a weld with fewer defects, in a preferred embodiment, a continuous rolling method is used to reduce the wire diameter, and the starting rolling temperature of the hot rough rolling is 500-530°C; and / or the starting rolling temperature of the hot finish rolling is 400-440°C.

[0038] The starting rolling temperature of hot rough rolling is set in a higher range, which helps to make the material have higher plasticity in the early stage of hot processing, reduce work hardening, and make the material easier to deform to further reduce cracks or fractures. The higher starting rolling temperature also helps to improve the fluidity of the material and facilitate the subsequent rolling process. The starting rolling temperature of hot finishing rolling in the above range can further improve the plasticity of the material, ensure that the wire size and shape can be finely controlled during the finishing rolling process, and reduce surface defects.

[0039] The use of wire drawing oil during the drawing process can protect the wire surface and prevent damage, while reducing the heat generated during the drawing process and ensuring the mechanical properties of the material. In a preferred embodiment, in step S6, wire drawing oil is also used for drawing, and the viscosity of the wire drawing oil is 90-110 mm 2 / s, density is 0.8~1.0g / cm 3 . High-viscosity wire drawing oil can form a thicker oil film between the metal wire and the die, provide good lubrication, reduce friction and wear during the drawing process, and further reduce scratches and other defects on the wire surface; it also helps to take away the heat generated during the drawing process to prevent the wire from overheating, thereby reducing the degradation of material properties caused by high temperature and improving the strength of the welding wire; during the drawing process, good lubrication can also reduce the adhesion between the metal wire and the die, reduce wire breakage problems, improve the continuity of the production process and the integrity of the welding wire, and help maintain the high-strength performance of the welding wire.

[0040] When the density of the wire drawing oil is within the above range, it can be better distributed evenly on the surface of the metal wire, so that all contact surfaces are well lubricated and a stable and complete oil film is formed, which is beneficial to improving the surface quality of the welding wire and reducing defects. The wire drawing oil with the above viscosity and density can provide better lubrication and cooling effects during the drawing process, reduce the friction and heat between the metal wire and the die, and the damage to the surface of the welding wire, while maintaining its high strength, it is also beneficial to make the welding wire have a higher surface quality.

[0041] In a preferred embodiment, the wire drawing oil includes, by weight, 20 to 30 parts of mineral oil, 40 to 50 parts of polyisobutylene, 15 to 25 parts of fatty acid ester, 10 to 15 parts of pentaerythritol ester and 1 to 3 parts of aniline antioxidant.

[0042] Among them, mineral oil can provide a stable lubrication basis to ensure the continuity of the processing process; polyisobutylene can enhance the adhesion of oil products, ensure that the wire drawing oil forms a uniform coverage on the surface of the welding wire, further improve the lubricity and prevent surface defects; pentaerythritol ester and fatty acid ester as efficient lubricants can significantly reduce the friction between the metal wire and the die, reduce surface scratches, and maintain surface smoothness; aniline antioxidants can effectively inhibit the oxidation of oil products, extend the service life of wire drawing oil, and indirectly support the maintenance of high surface quality. The above wire drawing oil composition can significantly improve the strength and surface quality of Al-Mg welding wire while facilitating processing, meeting the strict requirements of high-end application fields for welding wire performance.

[0043] In order to further promote the full dissolution of alloy elements and uniform microstructure, and lay a high-strength foundation for subsequent processing, in a preferred embodiment, the casting temperature is 720~760°C; and / or the homogenization temperature is 450~500°C, and the holding time is 10~24h. Homogenization treatment parameters within the above range are more conducive to eliminating casting stress, refining grains, further improving the comprehensive performance of the material, and reducing surface defects. The preferred extrusion ratio is 7~10, and the above extrusion ratio also helps to optimize the rheology of the material, improve the density of the internal structure of the welding wire, reduce defects such as pores, and improve the surface quality.

[0044] In another typical embodiment of the present invention, an Al-Mg welding wire is provided, which is obtained by the above-mentioned preparation method of the present invention. Due to the use of the preparation method of the present invention, it can take into account both high strength and high surface quality, and has significantly improved welding performance.

[0045] It should be noted that due to the particularity of the alloy field and the limitations of existing test characterization methods, it is difficult to comprehensively and quantitatively characterize the complex microstructure of the Al-Mg welding wire obtained above. Therefore, this application defines the Al-Mg welding wire with the above-mentioned preparation method, and controls the alloy composition, and uses homogenization and extrusion processes to evenly distribute the alloy elements, effectively eliminating component segregation, so that the welding wire has higher strength and improves the wire processing performance; at the same time, a reasonable wire processing process is adopted, and the rolling emulsion composition is regulated to improve the surface quality of the welding wire, so that the surface is flat, smooth, and scratch-free. The prepared finished welding wire can ensure the stable combustion of the arc and the molten pool during welding, thereby reducing defects such as weld porosity and effectively improving the weld quality. Experiments show that the Al-Mg welding wire obtained in this application has higher comprehensive mechanical properties.

[0046] Specifically, in a preferred embodiment, the strength of the Al-Mg welding wire is 450-500 MPa, and the strength of the deposited metal is 300-340 MPa.

[0047] In another typical embodiment of the present invention, a welding joint is provided, which is obtained by welding the above-mentioned Al-Mg series welding wire of the present invention with a 5XXX series plate. The weld grade is Grade I, and the grade standard is determined by CB / T 3747-2013 "Quality Requirements for Marine Aluminum Alloy Welded Joints". The weld defects are significantly reduced and the weld quality is significantly improved.

[0048] Typically but not limiting, the mass concentration of the hot rough rolling emulsion is 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10% or a range consisting of any two of them, and the pH value is 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7 or a range consisting of any two of them.

[0049] Typically but not limiting, the mass concentration of the hot rolling emulsion is 6%, 6.1%, 6.2%, 6.3%, 6.4%, 6.5%, 6.6%, 6.7%, 6.8%, 6.9% or a range consisting of any two of them, and the pH value is 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8 or a range consisting of any two of them.

[0050] Typical, but not limiting, viscosity of drawing oil is 90 mm 2 / s, 92 mm 2 / s, 95 mm 2 / s, 98 mm 2 / s、100mm 2 / s, 102 mm 2 / s, 105 mm 2 / s, 108 mm 2 / s, 110mm 2 / s or the range of any two of them, the density is 0.8 g / cm 3 , 0.85 g / cm 3 , 0.9 g / cm 3 , 0.95 g / cm 3 , 1.0 g / cm 3 Or a range of values ​​consisting of any two of them.

[0051] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0052] Example 1

[0053] A method for preparing an Al-Mg series welding wire, the composition of the Al-Mg series welding wire is shown in Table 1, and the preparation method comprises the following steps:

[0054] Step S1, smelting and casting high-purity aluminum ingots, magnesium blocks, copper blocks, aluminum-manganese master alloys, aluminum-iron master alloys and aluminum-titanium master alloys according to the composition ratio, using electromagnetic stirring to make the elements evenly distributed, using two-stage online degassing, introducing into a crystallizer for casting (casting temperature is 740° C.), and obtaining aluminum alloy cast bars with a diameter of φ=420 mm;

[0055] Step S2, homogenizing the aluminum alloy cast rod (temperature is 470° C., holding time is 18 h) to obtain an aluminum alloy billet;

[0056] Step S3, extruding the aluminum alloy billet (extrusion ratio is 8.3) to obtain an aluminum alloy extruded rod with a diameter of φ=145 mm;

[0057] Step S4, performing hot rough rolling (starting rolling temperature is 510° C.) on the aluminum alloy extruded rod, wherein a hot rough rolling emulsion is used for the hot rough rolling to obtain a hot rough rolled wire rod with a diameter of φ=25 mm;

[0058] Step S5, hot finishing rolling the rough hot rolled wire rod (start rolling temperature is 420°C), hot finishing rolling also uses hot finishing rolling emulsion, to obtain hot finishing rolled wire rod with φ=9mm;

[0059] Step S6, drawing the hot-rolled wire rod, using wire drawing oil to obtain a drawn wire rod with a diameter of φ=3.5 mm;

[0060] Step S7, coiling the drawn wire to obtain a coiled Al-Mg welding wire with a diameter of φ=1.2 mm that can be automatically fed.

[0061] The hot rough rolling emulsion and hot finishing emulsion used include 60 parts of mineral oil, 12 parts of trimethylol oleate, 8 parts of fatty hydrocarbons, 7 parts of dihydrated benzyldimethyltetradecylamine, 5 parts of ethoxylated fatty alkylamine, 4 parts of sodium petroleum sulfonate, 2 parts of N,N-dimethyldodecylamine N-oxide and 0.3 parts of phenolic antioxidant. The mass concentration of the hot rough rolling emulsion is 8.5% and the pH value is 6.5; the mass concentration of the hot finishing emulsion is 6.5% and the pH value is 7.5.

[0062] The wire drawing oil used includes 25 parts of mineral oil, 45 parts of polyisobutylene, 20 parts of fatty acid ester, 12 parts of pentaerythritol ester and 2 parts of aniline antioxidant. The viscosity of the wire drawing oil is 100 mm 2 / s, density is 0.9g / cm 3 .

[0063] Examples 2 to 5

[0064] The difference from Example 1 is that the composition of the Al-Mg series welding wire is different, see Table 1 for details.

[0065] Example 6

[0066] The difference from Example 1 is that the mass concentration of the hot rough rolling emulsion used is 7% and the pH value is 6; the mass concentration of the hot finishing rolling emulsion is 6% and the pH value is 7.1. The hot rough rolling emulsion and the hot finishing rolling emulsion include 50 parts of mineral oil, 10 parts of trimethylol oleate, 10 parts of fatty hydrocarbons, 5 parts of dihydrated benzyldimethyltetradecylamine, 6 parts of ethoxylated fatty alkylamine, 3 parts of sodium petroleum sulfonate, 3 parts of N,N-dimethyldodecylamine N-oxide and 0.1 parts of phenolic antioxidant.

[0067] Example 7

[0068] The difference from Example 1 is that the mass concentration of the hot rough rolling emulsion used is 10% and the pH value is 7; the mass concentration of the hot finishing rolling emulsion is 6.9% and the pH value is 8. The hot rough rolling emulsion and the hot finishing rolling emulsion include 70 parts of mineral oil, 15 parts of trimethylol oleate, 5 parts of aliphatic hydrocarbons, 8 parts of dihydrated benzyldimethyltetradecylamine, 3 parts of ethoxylated fatty alkylamine, 5 parts of sodium petroleum sulfonate, 1 part of N,N-dimethyldodecylamine N-oxide and 0.5 parts of phenolic antioxidant.

[0069] Example 8

[0070] The difference from Example 1 is that the viscosity of the wire drawing oil used is 90 mm 2 / s, density is 0.8g / cm 3The wire drawing oil includes 30 parts of mineral oil, 50 parts of polyisobutylene, 15 parts of fatty acid ester, 15 parts of pentaerythritol ester and 1 part of aniline antioxidant.

[0071] Example 9

[0072] The difference from Example 1 is that the viscosity of the wire drawing oil used is 110 mm 2 / s, density is 1.0g / cm 3 The wire drawing oil includes 20 parts of mineral oil, 40 parts of polyisobutylene, 25 parts of fatty acid ester, 10 parts of pentaerythritol ester and 3 parts of aniline antioxidant.

[0073] Example 10

[0074] A method for preparing an Al-Mg series welding wire, wherein the composition of the Al-Mg series welding wire is the same as that of Example 1, and the preparation method comprises the following steps:

[0075] Step S1, smelting and casting high-purity aluminum ingots, magnesium blocks, copper blocks, aluminum-manganese master alloys, aluminum-iron master alloys and aluminum-titanium master alloys according to the composition ratio, using electromagnetic stirring to make the elements evenly distributed, using two-stage online degassing, introducing into a crystallizer for casting (casting temperature is 720° C.), and obtaining aluminum alloy cast bars with a diameter of φ=420 mm;

[0076] Step S2, homogenizing the aluminum alloy cast rod (temperature is 450° C., holding time is 24 h) to obtain an aluminum alloy billet;

[0077] Step S3, extruding the aluminum alloy billet (extrusion ratio is 7) to obtain an aluminum alloy extruded rod;

[0078] Step S4, performing hot rough rolling (starting rolling temperature is 500° C.) on the aluminum alloy extruded rod, wherein the hot rough rolling also uses a hot rough rolling emulsion to obtain a hot rough rolled wire rod;

[0079] Step S5, hot finishing rolling the rough hot rolled wire rod (starting rolling temperature is 400° C.), hot finishing rolling also uses hot finishing rolling emulsion to obtain hot finishing rolled wire rod;

[0080] Step S6, drawing the hot-rolled wire rod, using wire drawing oil to obtain a drawn wire rod;

[0081] Step S7, coiling the drawn wire to obtain a coiled Al-Mg welding wire that can be automatically fed.

[0082] The hot rough rolling emulsion and hot finishing emulsion used include 60 parts of mineral oil, 12 parts of trimethylol oleate, 8 parts of fatty hydrocarbons, 7 parts of dihydrated benzyldimethyltetradecylamine, 5 parts of ethoxylated fatty alkylamine, 4 parts of sodium petroleum sulfonate, 2 parts of N,N-dimethyldodecylamine N-oxide and 0.3 parts of phenolic antioxidant. The mass concentration of the hot rough rolling emulsion is 8.5% and the pH value is 6.5; the mass concentration of the hot finishing emulsion is 6.5% and the pH value is 7.5.

[0083] The wire drawing oil used includes 25 parts of mineral oil, 45 parts of polyisobutylene, 20 parts of fatty acid ester, 12 parts of pentaerythritol ester and 2 parts of aniline antioxidant. The viscosity of the wire drawing oil is 100 mm 2 / s, density is 0.9g / cm 3 .

[0084] Embodiment 11

[0085] A method for preparing an Al-Mg series welding wire, wherein the composition of the Al-Mg series welding wire is the same as that of Example 1, and the preparation method comprises the following steps:

[0086] Step S1, smelting and casting high-purity aluminum ingots, magnesium blocks, copper blocks, aluminum-manganese master alloys, aluminum-iron master alloys and aluminum-titanium master alloys according to the composition ratio, using electromagnetic stirring to make the elements evenly distributed, using two-stage online degassing, introducing into a crystallizer for casting (casting temperature is 760° C.), and obtaining aluminum alloy cast bars with a diameter of φ=420 mm;

[0087] Step S2, homogenizing the aluminum alloy cast rod (temperature is 500° C., holding time is 10 h) to obtain an aluminum alloy billet;

[0088] Step S3, extruding the aluminum alloy billet (extrusion ratio is 10) to obtain an aluminum alloy extruded rod;

[0089] Step S4, performing hot rough rolling (starting rolling temperature is 530° C.) on the aluminum alloy extruded rod, wherein the hot rough rolling also uses a hot rough rolling emulsion to obtain a hot rough rolled wire rod;

[0090] Step S5, hot finishing rolling the rough hot rolled wire rod (starting rolling temperature is 440°C), hot finishing rolling also uses hot finishing rolling emulsion to obtain hot finishing rolled wire rod;

[0091] Step S6, drawing the hot-rolled wire rod, using wire drawing oil to obtain a drawn wire rod;

[0092] Step S7, coiling the drawn wire to obtain a coiled Al-Mg welding wire that can be automatically fed.

[0093] The hot rough rolling emulsion and hot finishing emulsion used include 60 parts of mineral oil, 12 parts of trimethylol oleate, 8 parts of fatty hydrocarbons, 7 parts of dihydrated benzyldimethyltetradecylamine, 5 parts of ethoxylated fatty alkylamine, 4 parts of sodium petroleum sulfonate, 2 parts of N,N-dimethyldodecylamine N-oxide and 0.3 parts of phenolic antioxidant. The mass concentration of the hot rough rolling emulsion is 8.5% and the pH value is 6.5; the mass concentration of the hot finishing emulsion is 6.5% and the pH value is 7.5.

[0094] The wire drawing oil used includes 25 parts of mineral oil, 45 parts of polyisobutylene, 20 parts of fatty acid ester, 12 parts of pentaerythritol ester and 2 parts of aniline antioxidant. The viscosity of the wire drawing oil is 100 mm 2 / s, density is 0.9g / cm 3 .

[0095] Comparative Example 1

[0096] The difference from Example 1 is that no hot rough rolling emulsion is used.

[0097] Comparative Example 2

[0098] The difference from Example 1 is that no hot finishing emulsion is used.

[0099] Comparative Example 3

[0100] The difference from Example 1 is that the mass concentration of the hot rough rolling emulsion used is 6%, and the pH value is 8; the mass concentration of the hot finishing rolling emulsion is 10%, and the pH value is 6.

[0101] The Al-Mg series welding wires prepared in the above-mentioned embodiments and comparative examples were subjected to strength tests and deposited metal strength tests. The results are shown in Table 2.

[0102] The Al-Mg series welding wires prepared in the above embodiments and comparative examples were welded to 5A06 plates to obtain welded joints. The weld grades were measured. The results are shown in Table 2.

[0103] The surface of the Al-Mg welding wire of Example 1 was observed using an electron microscope. Figure 1 It can be seen that there are no obvious scratches, pits or other obvious defects on the surface of the welding wire. Figure 2 It can be seen that the weld is well formed without obvious defects of unwelded and incomplete penetration. The engineering stress-strain curve of the weld joint (welding wire deposited metal) of Example 1 is shown in Figure 3 It can be seen that the tensile strength of the deposited metal can reach 330MPa.

[0104] Test method:

[0105] Strength of Al-Mg welding wire: GB / T 228.1-2021 "Tensile test of metallic materials Part 1: Room temperature test method".

[0106] Deposited metal strength and engineering stress-strain curve: GB / T 228.1-2021 "Tensile test of metallic materials Part 1: Room temperature test method".

[0107] Weld grade: CB / T 3747-2013 "Quality requirements for marine aluminum alloy welded joints".

[0108] Table 1

[0109]

[0110] Table 2

[0111]

[0112] It can be seen from the above that, compared with the comparative example, the embodiments of the present invention control the alloy composition and use homogenization treatment and extrusion process to evenly distribute the alloy elements, effectively eliminate component segregation, so that the welding wire has higher strength and improves the wire processing performance; at the same time, a reasonable wire processing technology is adopted, and the rolling emulsion composition is regulated to improve the surface quality of the welding wire, so that the surface is flat, smooth, and free of scratches. The prepared finished welding wire can ensure stable combustion of the arc and the molten pool during welding, thereby reducing defects such as weld porosity and effectively improving the weld quality.

[0113] In addition, it can be seen that when each process parameter is within the preferred range of the present invention, the overall effect is better.

[0114] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an Al-Mg welding wire, characterized in that: The Al-Mg welding wire comprises, by weight percentage, Si≤0.05%, Fe≤0.12%, Cu≤0.01%, Mn≤0.55%, 5.6%≤Mg≤6.6%, Ti≤0.08%, and the balance is Al and unavoidable impurity elements, single impurity≤0.05%, and total impurity≤0.15%; the preparation method comprises the following steps: Step S1, melting and casting the alloy raw materials according to the composition ratio to obtain aluminum alloy cast rods; Step S2, homogenizing the aluminum alloy cast rod to obtain an aluminum alloy billet; Step S3, extruding the aluminum alloy billet to obtain an aluminum alloy extruded rod; Step S4, performing hot rough rolling on the aluminum alloy extruded rod, wherein the hot rough rolling also uses a hot rough rolling emulsion to obtain a hot rough rolled wire rod; Step S5, performing hot finish rolling on the hot rough rolled wire rod, wherein the hot finish rolling also uses a hot finish rolling emulsion to obtain a hot finish rolled wire rod; Step S6, drawing the hot-rolled wire to obtain a drawn wire; Step S7, coiling the drawn wire to obtain the Al-Mg welding wire; The mass concentration of the hot rough rolling emulsion is greater than the mass concentration of the hot finishing rolling emulsion, and the pH of the hot rough rolling emulsion is less than the pH of the hot finishing rolling emulsion.

2. The preparation method according to claim 1, characterized in that: The mass concentration of the hot rough rolling emulsion is 7-10%, and the pH value is 6-7; and / or The mass concentration of the hot finishing emulsion is 6-6.9%, and the pH value is 7.1-8.

3. The preparation method according to claim 1 or 2, characterized in that: Respectively and independently, in parts by weight, the hot rough rolling emulsion and the hot finishing rolling emulsion include 50-70 parts of mineral oil, 10-15 parts of trimethylol oleate, 5-10 parts of aliphatic hydrocarbons, 5-8 parts of dihydrated benzyldimethyltetradecylamine, 3-6 parts of ethoxylated fatty alkylamine, 3-5 parts of sodium petroleum sulfonate, 1-3 parts of N,N-dimethyldodecylamine N-oxide and 0.1-0.5 parts of phenolic antioxidant.

4. The preparation method according to claim 1 or 2, characterized in that: The starting rolling temperature of the hot rough rolling is 500-530°C; and / or the starting rolling temperature of the hot finish rolling is 400-440°C.

5. The preparation method according to claim 1 or 2, characterized in that: In step S6, the drawing also uses drawing oil, and the viscosity of the drawing oil is 90-110 mm 2 / s, density is 0.8~1.0g / cm 3 .

6. The preparation method according to claim 5, characterized in that: In parts by weight, the wire drawing oil comprises 20 to 30 parts of mineral oil, 40 to 50 parts of polyisobutylene, 15 to 25 parts of fatty acid ester, 10 to 15 parts of pentaerythritol ester and 1 to 3 parts of aniline antioxidant.

7. The preparation method according to claim 1 or 2, characterized in that: The casting temperature is 720-760°C; and / or The homogenization temperature is 450-500° C., and the insulation time is 10-24 hours.

8. An Al-Mg welding wire, characterized in that: The method is used as claimed in any one of claims 1 to 7.

9. The Al-Mg welding wire according to claim 8, characterized in that: The strength of the Al-Mg welding wire is 450-500 MPa, and the strength of the deposited metal is 300-340 MPa.

10. A welding joint, characterized in that: The Al-Mg series welding wire according to claim 8 or 9 is used to weld with 5XXX series plates, and the weld grade is Grade I.

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